Until recently, the psychological mechanism of the interaction of the three kinds of information(Statistical information, experimental results, and testimonies) in children's scientific thinking has not been elucidated (Sobel & Kushnir, 2013). In this study, research paradigm from Bridgers et al(2016) was used in two experiments to explore the influence of order of two kinds of evidence: adult’s testimony and adult’s experiment, on 5-year-old children’s causal inference. children's perception of the level of testimony’s confidence also was analyzed. Experiment 1 adopted a 2×2 completely randomized experiment design, the independent variable was the informant’s self-confidence (two levels: self-confidence, not-confidence) and the order of evidence (two levels: testimony prior to experiment, experiment prior to testimony), the dependent variable was the frequency of children’s choice of candidate cause. Both testimony and experiment were given by an adult female in a laptop, in respective. 132 preschool children(77 boys and 55 girls, mean age 68.2 months) took part in experiment 1. The results showed that there were more children choice cause according to testimony in condition that experiment prior to testimony, and according to experiment in condition that testimony prior to experiment, resulting in a recency effect. children was not sensitive to the testimony’s confidence and informant’s awareness. Experiment 1 found that children was not sensitive to the testimony’s confidence, which might be unaware of the information of testimony’s confidence. Experiment 2 adopted the same experiment design of experiment 1, but appended a confidence question to the end of testimony. 127 preschool children(70 boys and 57 girls, mean age 69.3 months) took part in experiment 2. The results showed that there were more children in condition of confidence testimony than in condition of not-confidence testimony choice cause according to testimony, but the effect of evidence order were removed. It seemed that 5-year-old children gave the same weight to adult’s testimony and experiment, and the change of evidence order brought a recency effect on children’s causal inference, but recency effect would been eliminate by appending a confidence question to the end of testimony. That children was not sensitive to the self-confidence of testimony might be unaware of it. The follow-up Research should focus on the interaction of independent exploration, observing others experiment and informant testimony on preschool children's scientific thinking, on the influence of evidence strength and on how to improve children's scientific thinking in preschool curriculum.